Manny Pacquiao underwent surgery on his injured right shoulder Wednesday following his loss to Floyd Mayweather Jr. in boxing's richest fight ever.

Pacquiao spokesman Fred Sternburg quoted the fighter's surgeon, Dr. Neal ElAttrache of the Kerlan Jobe Orthopaedic clinic in Los Angeles, as saying he could not be "more pleased with the results" and fully expects Pacquiao to be back in the ring.

The surgery came four days after Pacquiao fought Mayweather at the MGM Grand hotel in Las Vegas, dropping a unanimous 12-round decision. Pacquiao asked for a pain killing shot before the fight for his shoulder, but was denied by Nevada boxing officials because they weren't aware previously of the injury.

Pacquiao said he thought he could fight after suffering an injury to the shoulder three weeks ago in training. He said he hurt it worse in the fourth round, when he landed some of his best punches of the night.

Nevada boxing officials are considering disciplinary action against Pacquiao for not disclosing the injury on a form the day before the fight.

There has also been a lawsuit filed in federal court in Las Vegas asking for fraud damages on behalf of people who spent money to watch the fight or bet on it. A similar suit has been filed in federal court in Chicago.